In Cygwin's supplied cvs package:
$ cvs --version
Concurrent Versions System (CVS) 1.11.23 (client/server)
Copyright (C) 2006 Free Software Foundation, Inc.
[..]
This seems to be an older version of cvs, and SourceForge's cvs server won't always interoperate with it to do e.g. the cvs remove command. Choices to install are 1.11.23-2 and the older 1.11.22-1.